Mortise and tenon joints are well known for many applications. The traditional joint used in timber construction uses wooden pegs to hold the tenon in the mortise. Joints are assembled by forcing the two members together, drilling a peg hole, and inserting the peg. In order to design for tension and shear loads, the depth and length of the tenon is relatively large in proportion to the beam size. This requires therefore a large mortise. This adversely affects the strength of the mortised beam and limits the number of joints at one location.
Many types of steel connectors are available to hold timbers together with bolts or screws. These are normally external and as such are often unattractive and prone to early failure during fire.